1. Field of the Invention
The present invention relates to an inertial device with the pedometer function and to a portable electric appliance incorporating said inertial device.
2. Description of the Related Art
As is known, a pedometer is a device that can be worn by a user and has the function of counting the number of steps during various forms of walking or running, for consequently estimating the distance covered. The indications provided are useful both for quantifying the motor activity performed by an individual in the course of a given period, for example for clinical purposes, and for evaluating performance in sport or even just for personal interest. Basically, a pedometer comprises a movement sensor, for detecting movements due to walking of a user, a control unit, which processes signals supplied by the movement sensor for counting the number of steps made, and a display, on which the important information is displayed. The elements that make up the pedometer are generally assembled on a board, which is in turn housed in a casing.
The growing interest for pedometers, the modest dimensions, and the relatively contained production cost have pushed manufacturers of different portable electronic devices to integrate in their own products also the pedometer function. In particular, some portable electronic devices are very well suited to integration of a pedometer, because they already comprise, for other purposes, some pedometer components. For example, cell phones and palmtops are always provided with a microprocessor that performs numerous control functions. Increasingly frequently, moreover, the same devices also include an inertial sensor, which, among other things, can be used for the purpose of detecting and recording traumatic events, such as impact and falls, or else for detecting states of prolonged rest, in which the devices are presumably unused and can be set in a low-consumption wait state or stand-by mode.
The integration of a pedometer poses, however, some problems. In fact, the procedures used for counting the steps become progressively more sophisticated and require a growing processing capacity, also because they are continuously executed for prolonged periods. For instance, the signal coming from the movement sensor is filtered and subjected to further processing to prevent events not correlated to walking from falsifying counting of the steps. On the other hand, the microprocessor executes the majority of the functions envisaged for the portable device, in addition to serving as control unit of the pedometer. Conflicts may thus arise, especially when the microprocessor is intensively exploited for other reasons (for example, for the reproduction of a digital film).